Umbrina bussing, a new sciaenid fish from the tropical eastern Pacific Ocean

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(1)Rev. Biol. Trop., 28( 1 ) : 203-208, 1 980. Umbrina bussingi, a new sciaenid fish from the. tropical eastern Pacific Ocean by Myrna. 1.. López S. *. (Received for publication January 1 5 , 1 980) Abstract: A new sciaenid fish from moderately deep water is described from the Pacific coast of Costa Rica. Umbrina bussingi is characterized by a relatively large eye, long pectoral fin, a single, laterally compressed mental barbel with an ellip tical pore and a low dorsal fin-ray count. In addition, the new species differs from its eastern Pacific congeners in lacking oblique black stripes on the sides. U. bussingi differs from its western Atlantic cognate species U. milliae in its longer pelvic rays, dorsal rays subequal in length and lower dorsal and anal-fin counts.. A new sciaenid fish was captured by the Spanish vessel Macuro during an exploratory fishing cruise in December 1 977 off the Pacific coast of Costa Rica at depths between 1 83 and 290 m. The fish has a simple swim bladder (no appendages) rounded anteriorly and sharply pointed posteriorly, and a short mental barbel, characters diagnostic of the tribe Umbrinini (Trewavas, 1 964; Gilbert, 1 966). UMBRINA B USSINGI, new species (Figs. 1 and 2) Holotype: LACM 3871 5 � 1 , 1 83.5 mm SL (standard length). V/Macuro sta tion 41 , Costa Rica, Central America, 09° 02' N ; 84° 1 3 ' W, taken between 1 83 and 290 m with semi-pelagic trawl, 1 9 December 1 977. Diagnosis: An Umbrina distinguished from its congeners by the combination of: a single, laterally compressed barbel with an elongate , elliptical pore on the anterior edge ; a relatively low number of soft dorsal rays; a large eye (9.5 percent of SL) and a long second anal spine . Meristic counts are dorsal fin XI, 2 1 ; anal fin n , 7; pectoral fin i, 1 7 ; gill rakers including rudiments 8 in upper arch, 1 1 in lower arch and 49 or 50 lateral line scales. *. Escuela de B iología y Centro de Investigación en Ciencias del Mar y Limnología, Univer sidad de Costa Rica. 203.

(2) 204. REVISTA DE BIOLOGIA TROPICAL. Description: Characters mentioned in the diagnosis for the species are not induded here. Proportion� in percentage of standard length are presented in Ta ble l . Body moderately elongate, laterally compressed; anterior dorsal profile gently convex; maximum depth between second dorsal spine and origin of pelvic fin, 3 .05 times in SL; slightly convex from pelvic fins to origin of anal fin and moderately concave aboye and below caudal pedunde. Head moderate , 3 .0 times in SL; snout length less than orbit diameter, 4.0 times in HL (head length) ; snout projecting beyond premaxillary a distance about equal to pupil diameter and wit� 5 upper I rostral pores and 5 marginal pores (Fig. 2D). Rostral flap divided into 4 small lobes. Mental pores 4, 2 on each side of median mental barbel; mental barbe!' with an anterior elliptical pore . Eyes large , orbit diameter 3 .4 times in HL. Least width of interorbital 5 .0 times in HL. Mouth inferior slightly oblique . Upper jaw projecting beyond lower jaw ; maxillary reaching anterior margin of pupil. Teeth of both jaws in broad bands decreasing in width at symphysis. AH teeth sharp and pointed , those on outer bands enlarged and more canine-like. Nares dose together, anterior ones more rounded and about width of posterior ones which are vertically elongate and situated immediately anterior to eye. Preoperde with serrated margin, serrae at angle most prominent. Gill rakers at angle of first arch largest, approximately length of anterior nares. Body covered with large ctenoid scales (49 or 50 in lateral line), largest scales on median line below middle of spinous dorsal fin base, about one-half eye diame ter . Head fully scaled; small cydoid scales below anterior nares to end of maxillary ; scales ctenoid on interorbital and rest of head and body. Basal one-fourth of caudal fin covered with small, elongate ctenoid scales. Dorsal fin with 1 1 spines, longest (fourth spine) 2.0 times in HL and reaching tenth dorsal spine when depressed. First dorsal fin spine smallest, less than pupil diameter; second spine equal to eye. Notch between dorsal fins not extending to dorsal-fin base. Dorsal fin rays 2 1 : last divided at its base. Anterior soft rays 'about 2.7 times in HL; last 5 decreasing in length, last ray 5 .0 times in HL. Pre-dorsal distan ce 2.7 times in SL. Anal fin with 2 spines, second spine heavy, large , as long as longest dorsal spine (2.0 times in HL) and with a pronounced groove on posterior surface ; second anal spine when depressed reaching vertical from end of dorsal base. First anal ray 2 .0 times in HL, last anal ray divided to base, 4 . 1 times in HL; anal-fin origin below the ninth dorsal soft rayo Preanal distance 4.7 times in HL. Length of anal-fin base 3 .7 times in HL. Pectoral fins i, 1 7 ; rather long, longest rays passing pelvic fins and almost reaching to aboye anus ( I .35 times in HL); pectoral origin just posterior to mem branous tip of operde ; lower margin indined obliquely and rays rapidly decreasing in length after fifth ray. Pelvic fins 1, 5, distal tips reaching a vertical from base of last dorsal spine ; origin below lower end of pectoral fin base. Length of pelvics 1 .7 times in HL. Prepelvic distance 2 .65 times in SL. Caudal fin with 1 4 branched rays; double truncate (upper lobe broken); midcaudal rays longest . Coloration: Color in ethyl alcohol brownish, scale centers silvery with dark pigmentation on borders; a small, faint blotch on upper sides of body, just below last three dorsal spines. Operdes and branchiostegal membranes appearing dark externally due to black lining of gill chambers. Head light brown with a great.

(3) t:- e. �. �. �. �. �.. g' í:l s·. �.. :> (1) � � (1) o. g. ....,. Fig. 1 .. Umbrina bussingi, new species. holotype, LACM 3 8 7 1 5 - 1 , 1 83 .5 Pacific coast of Costa RIca.. mm. SL, from the. �.

(4) 206. REVISTA DE BIOLOGIA TROPICAL. concentration of melanophores on snout, maxillaries, opercle and branchiostegals. Interradial membranes of spinous dorsal black anteriorly, paler basally posterior to the third dorsal spine . sOft dorsal fin dusky. Interradial membranes of anal fin black, darker between first thret: rays. Caudal fm base brown, distal two thirds black. Pectoral fm with scattered melanophores. Base of pelvic fins yellowish, distal half dark, two inner rays nearly colorless. Peritoneum with scattered melanophores. Otoliths: The sagitta is the only enlarged otolith (Figs. 2A to 2C). Its length is. one-half the eye diameter; the width is tw6-thirds of its length. The sagitta Hes obliquely in the sacculus with the smooth and convex suI'face inside, to the median axis. As in all sciaenids the sagitta is characterized by having on its inner surface a tadpole-shaPed sulcus; the anterior expanded portion, the ostium, is visible in out line, but is not channeled; the elongate bent portion, the cauda, is channeled. The outer surface has granulations on the antelior half (Fig. 2B). Vertebral counts: Umbrina bussingi has 9 precaudal and 1 5 caudal "ertebrae including the hypural plateo Other eastem Pacific Umbrina examined: U. xanti (2 specimens), U. galapago rum (5 specimens) and U. tumacoensis (4 specimens) also present 9 precaudal and 1 5 caudal vertebrae. Etymology: This species is named after my husband, William A. Bussing for his valuable contributions to the knowledge of Costa Rican ichthyofauna.. TABLE 1 Counts and measurements 01 Umbrina bussingi compared with two other species 01 Umbrina. Measurements are expressed in percent 01 standard length U. bussing (Pac.). Standard length Eye diameter Interorbital distance Head length Body depth Pectoral length Pelvic length Length second anal spine Dorsal fin rays Anal fm rays Pectoral fin rays Pelvic fi n rays Gill rakers in lower limb Total gill rakers Lateral line scales. *. After MUler (1971).. U. milliae*. (Atl.). U. xanti (Pac.). Holotype. Holotype. Paratype. 4 specimens (UCR). 183.5 mm 9.5 6.8 3 3.4 3 2.2 25.1 2 1 .8 1 7.4. 193 .0 mm 9.8 7.1 34.9 36.9 27.2 19.3 14.5. 1 60.0 mm 10.7 7.1 35.5 34.9 27.6 23.2 1 5 .7. 163 .0-205.0 mm 6.6- 7 .4 6 . 1 - 6.8 25.5- 29.7 27 .8- 30.3 17.6- 1 8 . 1 18.2- 20.3 1 1 .2- 1 2.6. XI,21 11,7 i,17 1,5 11 19 49. XI,23 11,7 18 1,5. XI,22 11,7 18 1,5. 19 48. 20 48. XI,28-29 II,6 i,1 5 - 1 7 1,5 7 - 10 13-16 5.3-5&...

(5) LOPEZ: Umbrina bussingi, new species. 207. Remarks: Trewavas (I 964) and Chao ( I 978) included Umbrina along with Ctenosciaena and Menticirr.hus in the sciaenids with a single mandibular barbel. Ctenosciaena has a thin ba·rbel without an apical pore . Umbrina and Mentici"hus have a barbel with an apical pore, however the latter group of species attains a greater size and has a longer, thinner mental barbel than the species of Umbrina. In addition to U bussingi, four other species of Umbrina from the the tropi cal eastem Pacific are probably valid: U xanti Gill , U dorsalis Gill, U ga/apagorum Steindachner and U tumacoensis Wilson. The new species has a larger eye , lower dorsal-ray count (21 vs. 25 -30) and a deeper body than U xanti, U ga/apagorum and U tumacoensis. U bussingi has a lower dorsal-ray count (2 1 vs. 29-33), more gill rakers on the lower limb of the gill arch ( I 1 vs. 6-9) and longer pectoral fins than U dorsalis. AH four other eastem Pacific Umbrina present conspicuous dark streaks along the rows of scales on the back and flanks, a pattern not found on U bussingi. The new form is closest to U milliae MiHer which is known only from the Atlantic coast of Colombia and the two probably represent yet another transame rican species pair ; U bussingi has a different shaped and more elongate apical pore , shorter pectoral and pelvic fins and different outline of the soft dorsal fin than U milliae.. A. ---. B. 1 mm. e. Fig. 2.. Sagitta, pore pattern and mental barbel of Umbrina bussingi. A, Inner surface; B , Outer surface; e , Lateral view. D , Snout and mental pore pattern. E, Lateral view of mental barbe!..

(6) REVISTA DE BIOLOGIA TROPICAL. 208. ACKNOWLEDGMENTS 1 am grateful to William A. Bussing for criticizing the manuscript; to Dr. Norma Chirichigno and Dr. Labbish Chao for their comments on the new species ; to Hubert Araya U. for recognizing the unique qualities of this fish ; and to Carlos García C. for preparing Figure 2. 1 want to thank Manuel Chavarría for reviewing the manuscript.. RESUMEN Se describe como nueva especie de la familia Sciaenidae , Umbrina bussingi de la costa Pacífica de Costa Rica. Además de esa especie, existen dos formas más en. esta zona del mismo género : U xanti y U dorsalis; la nueva especie se diferencia de ambas por la combinación de las siguientes características: número menor de radios dorsales, diámetro orbital mayor y diferente morfología del barbo mandibular y del patrón de coloración . Se considera a U. milliae. ricanas.. bussingi. como la especie cognada de U. del Atlántico de Colombia, constituyendo así otro par de formas transame. LlTERATURE CITED ataO, L.N.. 1 9 7 8.. A basis for c1assifying Western Atlantic Sciaenidae (feleostei: Perciformes) . NOAA Tech. Rep. NMFS Circ., 4 1 5 : 1 -64.. Otirichigno, N. Ctenosciaena peruviana. nov. sp. Una nueva especie de Sciaenidae. de la costa del 1 969. Perú. Inst. del Mar, Callao, Perú, Serie Informes Especiales, IM-48: 1 - 1 5 . Gilbert, C.R. 1 966. Western Atlantic sciaenid fishes of the genus Umbrina. Bull. Mar. Sci., 1 6 : 230-258. Meek, S.F., & S.F. Hildebrand 1 925. The marine fishes of Panama. Part 11. Field Mus. Nat. Hist. Pub!. 226 , Zoo!. Ser., 1 5 : 33 1-707 . Miller, R. V. 1971. A new sciaenid fish (Pisces: Umbrinini) with a single mental barbel, from the Southern Caribbean. Copeia, 1 97 1 : 300-306.. :rrewavas, E. 1. 964.. The sciaenid fishes with a single mental barbe!. Copeia, 1 964: 1 07 - 1 17 ..

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